THE Mount Magometon Quarry around thirty kilometres east of Coonamble was closed on Monday 28 August following an horrific workplace accident.

Emergency services were called out to the quarry following reports of an accident at about 3:45 pm that afternoon.

NSW Ambulance treated a 22 year-old man whose arm got caught in the mobile crushing plant after undertaking some maintenance on the plant.

He was airlifted to John Hunter Hospital and his arm was amputated from the elbow down, he remains in a serious condition.

The man was working for an external contractor.

SafeWork NSW was notified, and the regulator will attend the Coonamble Shire Council-operated Mount Magometon Quarry to investigate the incident and the circumstances behind it.

Council advised on Monday afternoon 28 August at around 5pm that the Quarry will be closed for several days.